CN104359493A - High-precision direction correction method under vehicle-mounted condition of smart phone - Google Patents

Abstract

The invention discloses a high-precision direction correction method under a vehicle-mounted condition of a smart phone. The method comprises the following steps: measuring the starting acceleration behavior of a vehicle by comprehensively using an acceleration sensor, a GPS sensor and a direction sensor which are embedded into the smart phone; and processing data measured by memory of the smart phone and estimating the included angle of the walking direction of the vehicle and the direction of the smart phone. Multiple experimental results verify that the method is very high in estimating precision and has a very good application prospect.

Description

High precision correction for direction method under smart mobile phone automobile scenarios

Technical field:

The present invention relates to a kind of high precision correction for direction method under smart mobile phone automobile scenarios.

Background technology:

Traffic safety is the focal issue of society.China's automobile pollution sharply increases in recent years.China's vehicle guaranteeding organic quantity breakthrough in the end of the year 2013 2.52.4 more than hundred million according to statistics, the number of operating motor vehicles reaches 2.82.6 hundred million.Meanwhile, also along with a large amount of appearance of traffic hazard.Nearly 200,000 of national traffic hazard in 2013, causes numerous casualties, causes massive losses to family and society.For improving this situation, except formulating more perfect traffic administration way and stricter driver training system, the driving condition to driver, drive route and traffic information is also needed to carry out real-time follow-up, set up more perfect management system, also can delimit for the responsibility after traffic hazard generation provides certain foundation.Specifically be described below:

Driving condition is followed the tracks of.Namely the driving condition of vehicle is followed the tracks of, especially effectively can reduce the generation of traffic hazard for the monitoring of drunk driving vehicle.The value of mobile phone acceleration sensor record is processed, and compares with each state value of typical drunk driving and can determine whether drunk driving and travel.The acceleration of this process need to vehicle decomposes the acceleration and side accekeration that comprise vehicle forward direction, and the correction accuracy of mobile phone coordinate system and vehicle axis system is especially crucial.

Drive route is followed the trail of.Comparatively simple drive route is followed the trail of with GPS module recording track now, but its limited accuracy.Though the positional information at vehicle place can be understood, can not to vehicle towards, situation of parking accurately judges, dangerous parking more easily causes traffic hazard, causes casualties.This method by smart mobile phone acceleration transducer judge driving condition (brake, turning, startup, deceleration etc.) can estimate more exactly vehicle stand, towards information such as, the gradients.These all need to estimate accurately vehicle axis system and mobile phone coordinate system.

Road conditions information gathering.Traditional road conditions method of estimation has the point of fixity such as wireless radio-frequency, license plate recognition technology to sample.Increased the method utilizing smart mobile phone to carry out road conditions estimation in recent years newly, and positioned mainly through base station, WIFI, GPS, infer traffic information with this.But the method has a lot of weak point: one is have the place of blocking accurately to locate in signal weakness, even can not position; Two is estimate road conditions by the method for location, have ignored the monitoring (starting parking phenomenon, acceleration and deceleration behavior, lane change situation, phenomenon of overtaking other vehicles frequently) to driving condition, can not make accurate judgement to the jam situation of road; Three is that combine with gps data and can judge current road conditions more accurately, real-time is higher if by the driving habit of acceleration transducer assistant GPS measuring vehicle; Four is that acceleration transducer can be tested by the flatness of degree of the jolting road pavement of measuring vehicle, helps people to select more reasonably traffic path.Similar to drive route method for tracing, need to correct accurately vehicle axis system and mobile phone coordinate system.

Because direction sensor is subject to the impact of electromagnetic equipment in car, and the deployment of some geographic location device can produce considerable influence, as television transmitting tower, broadcasting station, cellular base station, radar station, hi-line, transformer station etc. to terrestrial magnetic field.Therefore, someone once proposed to utilize acceleration transducer travel direction to correct, but stricter filtration is not carried out to data estimator, acceleration transducer travel direction is only used to correct, gross error even mistake can be brought due to the state of non-rectilinear brake, its method travel direction by emergency brake corrects and namely allows to obtain good estimated result, also affects the normal use of user to vehicle.

Summary of the invention

The object of the invention is to the deficiency for art methods, the method for the high precision correction for direction under a kind of smart mobile phone automobile scenarios is provided.

In order to realize above-mentioned object, the high precision correction for direction method under a kind of smart mobile phone of the present invention automobile scenarios takes following technical scheme, comprises the following steps:

(1) (mobile phone coordinate system is expressed as x' onboard by fixing for smart mobile phone, y', z', vehicle axis system is expressed as x, y, z), by repeatedly accelerating to start experiment, the acceleration (a of the acceleration transducer utilizing smart mobile phone embedded, GPS sensor and direction sensor collection vehicle _x', a _y', a _z'), speed ν, longitude and latitude, direction (w _x', w _y', w _z') and timestamp information;

(2) the mass data Negotiation speed gathered and directional information are filtered, select the acceleration information that effective linear accelerating starts; Be specially:

(2.1) speed collected by step (1) screens the starting state of vehicle: vehicle speed ν in 3s is starting state from the state that zero reaches 1.5m/s;

(2.2) from the starting state that step (2.1) filters out, linear starting transport condition is filtered out further: vehicle launch state is analyzed, for direction undulating quantity (w in start-up course _{y '}the difference of maxima and minima) be linear starting transport condition within 4 degree;

(2.3) from the linear starting transport condition that step (2.3) filters out, effective linear starting transport condition is filtered out further: acceleration>=0.2m/s ²moment be the vehicle launch true moment, speed is GPS time delay from zero to moment of non-zero change and mistiming in above-mentioned true moment, choose GPS time delay≤3.5s time be effective linear starting transport condition;

(3) direction calculating of the linear starting transport condition filtered out by step (2) obtains x, the relation between y, z and x', y', z': be specially:

Vehicle axis system is obtained coordinate system x after its Z axis turns clockwise α angle ₁, y ₁, z ₁, then after its X-axis is rotated counterclockwise β angle, obtain x ₂, y ₂, z ₂, be finally rotated counterclockwise γ angle around its Y-axis, overlap with mobile phone coordinate system after vehicle axis system is rotated through three times, β angle equals the w of the effective linear starting transport condition that step (2) filters out _{y '}mean value; γ angle equals the w of the effective linear starting transport condition that step (2) filters out _{z '}mean value; Obtain mobile phone towards the α angle with vehicle forward direction according to the accekeration of surface level, tried to achieve by following formula,

α=arctan (a _y1/ a _x1)+90, a _x1<0, a _y1<0 or a _x1<0, a _y1>0

α=arctan (a _y1/ a _x1)+270, a _x1>0, a _y1<0 or a _x1>0, a _y1>0

Wherein, a _x1represent at coordinate system x ₁, y ₁, z ₁middle x ₁the acceleration in direction, a _y1represent at coordinate system x ₁, y ₁, z ₁middle y ₁the acceleration in direction, is obtained by following formula:

$\left[\begin{array}{c}{a}_{x1}\\ a_{y1}\\ a_{z1}\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}\stackrel{\&OverBar;}{a_{x^{\text{'}}}}\\ \stackrel{\&OverBar;}{a_{y^{\text{'}}}}\\ \stackrel{\&OverBar;}{a_{z^{\text{'}}}}\end{array}\right]$

for effectively start state acceleration a _{x '}mean value; for effectively start state a _{y '}mean value; for effectively start state a _{z '}mean value; a _z1represent at coordinate system x ₁, y ₁, z ₁middle z ₁the acceleration in direction;

Obtain coordinates correction relational expression as follows:

$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& \sin \mathrm{\&alpha;}& 0\\ -\sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}{x}^{\text{'}}\\ y^{\text{'}}\\ z^{\text{'}}\end{array}\right].$

The invention has the beneficial effects as follows, the comprehensive utilization acceleration transducer of smart mobile phone, direction sensor and GPS achieve the method for conversion between vehicle axis system and mobile phone coordinate system and correction by the starting state of measuring vehicle.Simple to operate in correction for direction process, efficiency is high, and has very high estimated accuracy, has good application prospect.

Accompanying drawing explanation

Fig. 1 is vehicle axis system x, y, z and mobile phone coordinate system x', y', z' schematic diagram;

Fig. 2 is vehicle axis system and the diagram of mobile phone ordinate transform relation;

Fig. 3 is correction for direction process flow diagram;

Fig. 4 is the graph of a relation of direction undulating quantity and sample size;

Fig. 5 is gps data time delay and correction for direction precision;

Fig. 6 is α many correction for direction result schematic diagrams;

Fig. 7 is β many correction for direction result schematic diagrams;

Fig. 8 is γ many correction for direction result schematic diagrams;

Fig. 9 is that real vehicle axis system acceleration information and the inventive method correct the vehicle axis system acceleration information comparison diagram obtained.

Embodiment

The invention discloses a kind of acceleration transducer, direction sensor and the GPS that fully utilize smart mobile phone, achieved the method for conversion between vehicle axis system and mobile phone coordinate system and correction by the starting state of measuring vehicle.Simple to operate in correction for direction process, efficiency is high, and has very high correction accuracy, has good application prospect.Because direction sensor is subject to the impact of geographical environment, and the electron device of automotive metal iron sheet and Che Nei all can to the magnetic fields around mobile phone, the vehicle magnetic field intensity that diverse location is not different in the same time all can have difference, carries out correction error larger with direction sensor.The present invention's acceleration transducer travel direction corrects, and process flow diagram, as Fig. 3, mainly comprises the following steps:

(1) vehicle launch status information capture.As shown in Figure 1, fixed onboard by smart mobile phone, vehicle axis system is expressed as x, y, z; Mobile phone coordinate system is expressed as x', y', z'.By repeatedly accelerating to start experiment, the acceleration of the acceleration transducer utilizing smart mobile phone embedded, GPS sensor and direction sensor collection vehicle, speed, longitude and latitude, direction and timestamp information.In the present embodiment, we cooperate with taxi company, and gather the Acceleration of starting behavior of different driver, data acquisition session is completed by self-designed APP, and period does not limit the driving locus, driving time etc. of taxi.Share three mobile phones to have carried out accelerating for 4732 times to start experiment, the direction value that mobile phone records is (w _{x '}, w _{y '}, w _{z '}), accekeration is (a _{x '}, a _{y '}, a _{z '}).

(2) the mass data Negotiation speed gathered and directional information are filtered, select the acceleration information that effective linear accelerating starts.

(2.1) speed collected by step (1) screens the starting state of vehicle: the present invention utilizes the starting state of velocity measuring vehicle, and utilizes the direction undulating quantity of mobile phone to determine whether linear starting transport condition.In vehicle launch process, we choose speed in 3s is starting state from the state that zero reaches 1.5m/s;

(2.2) from the starting state that step (2.1) filters out, linear starting transport condition is filtered out further: in experiment, vehicle parking mode is complicated, stopping when starting and there will be acceleration turning starting state in vehicle side, tackles this and design corresponding filter algorithm in experiment.In experiment to mobile phone in vehicle launch process towards undulating quantity (w in start-up course _{y '}the difference of maxima and minima) data within 10 degree totally 2832 experiments add up, towards the relation of undulating quantity and sample size in start-up course, as Fig. 4.Size towards undulating quantity becomes parabolic relation with between sample size, in order to obtain higher effective sample volume guarantor to while correction accuracy, in experiment, we choose the decision threshold that the situation being not more than 4 degree (differences of maximal value and minimum value) towards undulating quantity is linear starting transport condition.

(2.3) from the linear starting transport condition that step (2.3) filters out, effective linear starting transport condition is filtered out further: due to time static, accekeration is all less than 0.2m/s ², during vehicle launch, accekeration is generally greater than 0.5m/s ², in the present embodiment, choose acceleration>=0.2m/s ²moment be the vehicle launch true moment, speed is GPS time delay from zero to the moment of non-zero and the mistiming in above-mentioned true moment.Because gps data Information Monitoring has the regular hour to postpone, need in experiment to measure time delay gps data.When being 4 degree towards fluctuation threshold value, gps data time delay and correction for direction precision are as Fig. 5.In order to obtain effective status as much as possible while guarantee precision, choosing GPS time delay is 3.5s.The situation of change of Negotiation speed of the present invention, correct effective sample towards undulating quantity and GPS filtering direction time delay, the state meeting these three conditions is called effective starting state.2117, effectively start sample is selected altogether in experiment.

(3) direction calculating of the linear starting transport condition filtered out by step 2 obtains x, and the relation between y, z and x', y', z', is specially:

The accekeration travel direction choosing the effectively start state meeting (2) corrects.Ask for angle and the transformational relation thereof of mobile phone coordinate system and vehicle axis system as the acceleration of vehicle forward direction using the acceleration of linear accelerating startup.Vehicle axis system is obtained coordinate system x after its Z axis turns clockwise α angle ₁, y ₁, z ₁, then after its X-axis is rotated counterclockwise β angle, obtain x ₂, y ₂, z ₂, be finally rotated counterclockwise γ angle around its Y-axis, overlap with mobile phone coordinate system, as Fig. 2 after vehicle axis system is rotated through three times.

β angle equals the w of the effective linear starting transport condition that step (2) filters out _{y '}mean value; γ angle equals the w of the effective linear starting transport condition that step (2) filters out _{z '}mean value; Obtain mobile phone towards the α angle with vehicle forward direction according to the accekeration of surface level, tried to achieve by following formula,

α=arctan (a _y1/ a _x1)+90, a _x1<0, a _y1<0 or a _x1<0, a _y1>0

α=arctan (a _y1/ a _x1)+270, a _x1>0, a _y1<0 or a _x1>0, a _y1>0

Wherein, a _x1represent at coordinate system x ₁, y ₁, z ₁middle x ₁the acceleration in direction, a _y1represent at coordinate system x ₁, y ₁, z ₁middle y ₁the acceleration in direction, is obtained by following formula:

$\left[\begin{array}{c}{a}_{x1}\\ a_{y1}\\ a_{z1}\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}\stackrel{\&OverBar;}{a_{x^{\text{'}}}}\\ \stackrel{\&OverBar;}{a_{y^{\text{'}}}}\\ \stackrel{\&OverBar;}{a_{z^{\text{'}}}}\end{array}\right]$

for effectively start state acceleration a _{x '}mean value; for effectively start state a _{y '}mean value; for effectively start state a _{z '}mean value; a _z1represent at coordinate system x ₁, y ₁, z ₁middle z ₁the acceleration in direction;

Mobile phone towards the α correction accuracy with vehicle forward direction angle as Fig. 6, the correction accuracy of mobile phone x-axis rotated counterclockwise by angle β as Fig. 7, around the correction accuracy of y-axis rotated counterclockwise by angle γ as Fig. 8.α distribution is more concentrated, and the difference of maxima and minima is all less than 20 degree, and the standard deviation of angle estimation is all less than 4 degree, and value-at-risk and precision have very high practical value, and the mean square deviation of β and γ is all less than 1, and evaluated error is less.

(4) conversion relational expression set up between vehicle axis system and mobile phone coordinate system is as follows:

$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& \sin \mathrm{\&alpha;}& 0\\ -\sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}{x}^{\text{'}}\\ y^{\text{'}}\\ z^{\text{'}}\end{array}\right].$

(5) according to above formula, vehicle all directions accekeration is verified, is specially:

Ask for the accekeration of each sampling instant vehicle forward direction, vertical direction and side direction according to the coordinate transformation relation formula in (4), mobile phone coordinate system is converted into vehicle axis system.Real vehicle axis system acceleration information and coordinate conversion rear vehicle coordinate system acceleration information are as Fig. 9.As seen from the figure, the true accekeration degree of agreement of coordinate conversion post-acceleration value and vehicle axis system is very high, owing to being that different mobile phones is placed on vehicle diverse location at synchronization and measures acceleration, so there is no fit like a glove, but dynamic change trend and the relevant information of accekeration can be reflected equally, there is very high practical value.

Claims (1)

1. the high precision correction for direction method under smart mobile phone automobile scenarios, it is characterized in that, the method comprises the following steps:

(1) smart mobile phone is fixed on vehicle, suppose that mobile phone coordinate system is expressed as x', y', z', vehicle axis system is expressed as x, y, z, by repeatedly accelerating to start experiment, the acceleration (a of the acceleration transducer utilizing smart mobile phone embedded, GPS sensor and direction sensor collection vehicle _x', a _y', a _z'), speed ν, longitude and latitude, direction (w _x', w _y', w _z') and timestamp information;

(2) the data Negotiation speed gathered and directional information are filtered, select the acceleration information that effective linear accelerating starts; Be specially:

(2.1) speed collected by step (1) screens the starting state of vehicle: vehicle speed ν in 3s is starting state from the state that zero reaches 1.5m/s;

(2.2) from the starting state that step (2.1) filters out, linear starting transport condition is filtered out further: vehicle launch state is analyzed, for direction undulating quantity (w in start-up course _{y '}the difference of maxima and minima) be linear starting transport condition within 4 degree;

(2.3) from the linear starting transport condition that step (2.3) filters out, effective linear starting transport condition is filtered out further: acceleration>=0.2m/s ²moment be the vehicle launch true moment, speed is GPS time delay from zero to moment of non-zero change and mistiming in above-mentioned true moment, choose GPS time delay≤3.5s time be effective linear starting transport condition;

(3) direction calculating of the linear starting transport condition filtered out by step (2) obtains x, the relation between y, z and x', y', z': be specially:

Vehicle axis system is obtained coordinate system x after its Z axis turns clockwise α angle ₁, y ₁, z ₁, then after its X-axis is rotated counterclockwise β angle, obtain x ₂, y ₂, z ₂, be finally rotated counterclockwise γ angle around its Y-axis, overlap with mobile phone coordinate system after vehicle axis system is rotated through three times, β angle equals the w of the effective linear starting transport condition that step (2) filters out _{y '}mean value; γ angle equals the w of the effective linear starting transport condition that step (2) filters out _{z '}mean value; Obtain mobile phone towards the α angle with vehicle forward direction according to the accekeration of surface level, tried to achieve by following formula,

α=arctan (a _y1/ a _x1)+90, a _x1<0, a _y1<0 or a _x1<0, a _y1>0

α=arctan (a _y1/ a _x1)+270, a _x1>0, a _y1<0 or a _x1>0, a _y1>0

Wherein, a _x1represent at coordinate system x ₁, y ₁, z ₁middle x ₁the acceleration in direction, a _y1represent at coordinate system x ₁, y ₁, z ₁middle y ₁the acceleration in direction, is obtained by following formula:

$\left[\begin{array}{c}{a}_{x1}\\ a_{y1}\\ a_{z1}\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}\stackrel{\&OverBar;}{a_{x^{\&prime;}}}\\ \stackrel{\&OverBar;}{a_{y^{\&prime;}}}\\ \stackrel{\&OverBar;}{a_{z^{\&prime;}}}\end{array}\right]$

for effectively start state acceleration a _{x '}mean value; for effectively start state a _{y '}mean value; for effectively start state a _{z '}mean value; a _z1represent at coordinate system x ₁, y ₁, z ₁middle z ₁the acceleration in direction;

Obtain coordinates correction relational expression as follows:

$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& \sin \mathrm{\&alpha;}& 0\\ -\sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&gamma;}& 0& -\sin \mathrm{\&gamma;}\\ \sin \mathrm{\&beta;}\sin \mathrm{\&gamma;}& \cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}\cos \mathrm{\&gamma;}\\ \cos \mathrm{\&beta;}\sin \mathrm{\&gamma;}& -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}\cos \mathrm{\&gamma;}\end{array}\right]\left[\begin{array}{c}{x}^{\&prime;}\\ y^{\&prime;}\\ z^{\&prime;}\end{array}\right].$